1. Field of the Invention
The present invention relates to method and apparatus for controlling the output of a power generation system using a single input power controller.
2. Related Background
In the field of engine control, many proposals exist for controlling the flow of fuel to the engine in accordance with detected engine operating parameters such as engine temperature, engine pressure ratio, shaft speed, etc. to maximize fuel efficiency, but such proposals fail to take into account the ambient operating conditions. Proposals of this type are described in U.S. Pat. Nos. 4,248,042; 4,551,972; 4,686,825; 5,029,778; 5,039,037; 5,277,024; and 5,613,652. However, even if such systems were adapted to power generation systems such as used by electric utilities, technicians would still be required to operate and continually adjust a plurality of control levers to optimize engine output for given environmental conditions.
By 1985, it was recognized that aircraft engine efficiency is highest when the engine is run with the throttle butterfly valve fully open and the desired performance is obtained by varying propeller speed. See, for example, SAE Technical Paper Series 850895, The Porsche Aircraft Engine P F M 3200″, Helmuth Bott and Heinz Dorsch, 1985. This article proposed a single-lever control system for an aircraft engine that operates both the throttle and the propeller governor with a single lever. However, the proposed system is a mechanical linkage system which accordingly cannot optimize engine performance based on various ambient flight conditions. That is, the Porsche system may work well at a single altitude, speed, and temperature, but will seriously degrade at other flight conditions.
Similarly, it may be advantageous in a power generation system, to allow the prime mover or engine to operate at a full throttle condition, while manipulating the attached electrical generator and/or connecting gear box to achieve maximum efficiency based on current environmental parameters. This approach may also be applied to wind turbine applications as well as propulsion systems for ground vehicles.